1. Field
This invention relates to medical apparatus, and more particularly to guide wires that are placed inside the body to guide a cannula to a desired position and kits therefor.
2. State of the Art
Today many different kinds of cannulas are inserted into patients for administering a wide variety of therapies. For example, a catheter of the type which is comprised of a trocar and a cannula may be inserted into a blood vessel to, for example, administer different fluids including whole blood, salt solution, and other therapeutic liquids through the cannula after removal of the trocar. The catheter may also be used to place instruments and to remove blood. U.S. Pat. No. 4,553,960 (Lazarus et al.) illustrates and describes a peritoneal lavage procedure employing a catheter and a cannula inserted into the peritoneal cavity.
In some instances, it is desirable to position a fairly large cannula within the body in a particular position or location. Positioning of such a large cannula through the skin can be difficult. Similarly, it may be difficult to direct the larger cannula to the appropriate or desired location within the body. Accordingly, today a guide wire may be prepositioned to guide the larger cannula. That is, a small trocar may be used to penetrate the skin and desirably to position a small diameter cannula in a desired location. After removal of the trocar, a guide wire is inserted through the in-place cannula and directed further interior the patient through, for example, a blood vessel. The cannula may then be removed over the guide wire and the larger cannula slid over the guide wire to follow the guide wire through the body to the desired location. U.S. Pat. No. 4,553,960 (Lazarus et al.) illustrates another use of such a guide wire. U.S. Pat. No. 4,545,390 (Leary) also describes use of a guide wire. U.S. Pat. No. 4,534,363 discloses a special form of guide wire.
The guide wires heretofore known are spring wound and similar in structure to piano wire. In some instances, they have varying diameters between a distal or interior end and an exterior or proximal end. Such wires are typically sized to be positioned through the interior of small cannulas and in a fashion similar to that illustrated in U.S. Pat. No. 4,553,960. In some instances, a hollow needle may be used without a cannula. That is, the hollow needle is inserted into the patient after which a guide wire is inserted through the hollow needle.
No guide wire has yet been suggested which in use would minimize the number of procedural steps associated with the positioning of a large catheter or minimize the steps associated with the cannulation of a patient when a guide wire is used.